Pituitary Histology

Question 1

Are there ducts in the endocrine system?

Answer 1

no

Question 2

If vascularizaiton rich or poor in the endocrine system?

Answer 2

rich - so the hormones can get into the blood

Question 3

The cells of the endocrine system are derived from what?

Answer 3

epithelium

Question 4

What is necessary for a hormone to enact it’s function?

Answer 4

there needs to be the right receptor on the target cell

Question 5

What are the endocrine glands that secrete amino acid-derivative hormones?

Answer 5

pituitary, thyroid, parathyroid, pancreatic islets

Question 6

What germ layers do these glands develop from?

Answer 6

endocerm or ectoderm

Question 7

What glands will secrete steroid hormones?

Answer 7

gonads and adrenal cortex

Question 8

What germ layer do the gonads and adrenal cortex derive from?

Answer 8

mesoderm

Question 9

What organelle will be particularly prominent in the glands that secrete steroids (the gonads and adrenal cortex)?

Answer 9

SER

Question 10

How does the location of the target receptors differ between the amino acid hormones and steroid hormones?

Answer 10

amino acid hormones have receptors on the cell surface

steroids have receptor in the cytoplasm

Question 11

What tissues of the enrocine system have discrete glands?

Answer 11

pituitary
pineal
thyroid
parathyroids
adrenals

Question 12

What tissues of the endocrine system have both endocrine and exocrine function?

Answer 12

kidney, pancreas, gonads, placenta

Question 13

What are the individual cells throughout the GI tract that are involved in the endocrine system?

Answer 13

DNES cells

Question 14

What are the two parts of the pituitary?

Answer 14

adenohypophysis

neurohypophysis

Question 15

How is the adenohypophysis derived?

Answer 15

from oral ectoderm

rathke’s pouch grows up from the roof ot he mouth to join the neurohypophysis

Question 16

How is the neurohypophysis derived?

Answer 16

it’s neural ectoderm growing down off the diencephalon

Question 17

What are the three parts of the adenohypophysis?

Answer 17

Pars tuberalis
Pars distalis (makes up most of the pituitary gland)
pars intermedia

Question 18

What are the two parts of the neurohypophysis?

Answer 18

pars nervosa

infundibulum (neural stalk)

Question 19

What system of blood vessels will deliver neurosecretory hormones from the primary capillary plexus of the median eminence to the secondary capillary plexus of the pars distalis?

Answer 19

the hypophyseal portal system of veins

Question 20

Describe the parenchyma of the pars disatlis.

Answer 20

it’s anastomosin cords of cells with sinusoidal capillaries in between

some glassy-looking colloid

Question 21

What are the two general cell types within the pars distalis. Exaplain the difference….

Answer 21

chromophobes (don’t take up stain)
Chromphils (take up stain) (about 50%)

note that the chromophobes are probably just chromophils that have lost their granules (about 50%)

Question 22

What are the two types of chromophils? Which is more prevalent?

Answer 22

Acidophils (most prevalent)

basophils

Question 23

What color do the acidophils stain?

Answer 23

red

Question 24

What are the two kinds of acidophils?

Answer 24

somatotrophs

mammotrophs

Question 25

What do the somatotrophs secrete?

Answer 25

growth hormone (or somatotropin)

Question 26

What do the mammotrophs secrete?

Answer 26

prolactin | so increase in number during pregnancy and lactation

Question 27

What are the three types of basophils?

Answer 27

thyrotrophs gonadotrophs corticotrophs

Question 28

What do the thyrotrophs secrete?

Answer 28

thyroid stimulating hormone (TSH)

Question 29

What do the gonadotrophs secrete?

Answer 29

Follicle stimulating hormone (FSH) and Lutenizing hormone (LH in females and interstitial stimulating homrone (ICSH) in males

Question 30

In the gonadotrophs, are the FSH and LH stored in the same secretory vesicles or different ones?

Answer 30

same ones

Question 31

What do corticotrophs secrete?

Answer 31

two things... adrenocorticotropic hormone (ACTH) Melanocyte-stimulating hormone (MSH)

Question 32

True or false: the pars intermedia is well-developed in humans

Answer 32

false - it's rudimentary

Question 33

Are the pars intermedia cells weakly basophilic or acidophilic?

Answer 33

basophilic

Question 34

What do they produce?

Answer 34

melanocyte-stimulating hormones (MSH)

Question 35

There are cysts within the pars intermedia - what are they derived from?

Answer 35

they are remnant of Rathke's pouch follicles lined by cuboidal epithelium and filled with colloid

Question 36

Why is the pars tuberalis such a highly vascularized area?

Answer 36

the superior hypophyseal arteries terminate here to form the primary plexus of portal veins

Question 37

The cells of the pars tuberalis are basophilic and contain what hormones?

Answer 37

FSH and LH

Question 38

What is the pars nervosa largely composed of?

Answer 38

about 100,000 secretory nerve cells

Question 39

Are these secretory nerve cells myelinated?

Answer 39

no

Question 40

Where are the cell bodies of these secretory nerve cells?

Answer 40

in the supraoptic and paraventricular nuclei of hypothalamus

Question 41

What is this tract of nerves called?

Answer 41

the hypothalamic-hypophyseal stalk

Question 42

THe pars nervosa has neurosecreotry vesicles synthesized in the cell bodies. What do they contain?

Answer 42

oxytocin or vasopressin ATP neurophysins

Question 43

What are neurophysins?

Answer 43

specific binding proteins for oxytocin and vasopressin

Question 44

Where do these neurosecretory vesicles accumulate?

Answer 44

herring bodies, which are dilated terminals adjacent to capillaries

Question 45

What are the supportive cells found throughout the neural lobe (most similar to astrocytes)?

Answer 45

pituicytes | they are the nuclei that you can see in the pars nervosa

Question 46

Which hypothalamic nuclei has cell bodies where most oxytocin is held?

Answer 46

the paraventricular

Question 47

WHat will trigger secretion of oxytocin?

Answer 47

suckling (milk ejection reflex)

Question 48

What does oxytocin cause?

Answer 48

contraction of the myoepthelial cells surorunding the alveoli and alveolar ducts of the mammary glands also stimulates uterine smooth muscle contraction

Question 49

What hypothalamic nucleus mainly has the vasopressin?

Answer 49

the supraoptic nucleus

Question 50

What does vasopressin (ADH) do?

Answer 50

increases permeability of distal convoluted and collecting tubules to water to increase resorption and concentrate urine

Question 51

What will stimualte ADH secretion?

Answer 51

increased plasma osmolality | decreased blood volume